1. Field of Inventive Concepts
The inventive concepts disclosed herein are generally directed to pluggable module housing assemblies. More particularly, but not by way of limitation, the inventive concepts disclosed herein are directed to pluggable module housing assemblies including riding heat sinks configured to be moved so as to avoid contacting a pluggable module during insertion of the pluggable module into a pluggable module housing and moved into contact with the pluggable module so as to form a thermal interface with the pluggable module once the pluggable module is inserted in the pluggable module housing.
2. Brief Description of Prior Art
Circuit packs including pluggable module housings are deployed in various networks and are configured to allow for the hot insertion (e.g., insertion in the field without disassembling the circuit pack) of a variety of pluggable modules, such as transceivers, optical modules, XFP modules, SFP+ modules, or CFP modules, for example. Pluggable modules are generally plugged in or inserted into a pluggable module housing by sliding or otherwise inserting the module into the housing. Several industry standards have been developed to standardize pluggable module housings and to set insertion force requirements for pluggable modules.
Heat generated by pluggable modules during operations is typically dissipated by one or more heat exchangers or heat sinks thermally coupled with the pluggable modules and/or with the pluggable module housings.
Recently, riding heat sinks have been incorporated into pluggable module housings by being mounted, clamped, or otherwise positioned into the pluggable module housing so that a large thermal interface is formed between contact surfaces of the riding heat sink and a pluggable module inserted in the pluggable module housing, and so that a predetermined amount of clamping force is exerted by the riding heat sink on the pluggable module at the thermal interface. Typically, as the pluggable module is inserted into the housing, a contact surface of the pluggable module presses against and slides under a module-contacting surface of the riding heat sink, which results in the module-contacting surface of the heat sink and the contact surface of the pluggable module sliding over one another each time a pluggable module is inserted into, or removed from, the housing.
Friction between the surfaces of riding heat sinks and pluggable modules results in a certain amount of insertion force being used to insert the pluggable module into the pluggable module housing. The amount of insertion force used to insert or remove a pluggable module is regulated by industry standards designed to prevent damage to the pluggable module housing, the riding heat sink, and the pluggable module. For example, currently applicable multi-source agreement (MSA) standards call for a pluggable module to be inserted into a pluggable module housing with a maximum insertion force of eighteen pounds (or 80 N), which effectively limits the clamping force at the thermal interface between the riding heat sink and the pluggable module to about three pounds or less.
Factors affecting the thermal efficiency of the riding heat sink include the smoothness or roughness of the contact surfaces forming the thermal interface between the heat sink and the pluggable module, and the clamping force exerted on the thermal interface. The applicable maximum insertion force standard is one practical limitation of the thermal efficiency of existing pluggable module housings having riding heat sinks. Another limitation arises from the possibility of contact surface damage due to repeated insertions and removals of pluggable modules in the housing. The contact surface of the riding heat sink and/or the contact surface of the pluggable module may become scratched, gouged, or otherwise roughened or damaged due to abrasion of the surfaces as a result of the surfaces rubbing against one another each time a pluggable module is inserted or removed.
To that end, what is need is a pluggable module housing assembly which allows insertion of the pluggable module into the pluggable module housing with a minimal amount of force, and which has a riding heat sink with an optimal thermal efficiency. It is to such an improved pluggable module housing assembly that embodiments of the present disclosure are directed.